Uche Ikpeazu's superb strike saw the Chairboys overcome play-off bound Bournemouth which, coupled with results elsewhere, delays a relegation that has long seemed inevitable.
Only a near-impossible set of circumstances, featuring a big win at Middlesbrough, a narrow victory for Sheffield Wednesday over Derby, dropped points for Rotherham and a staggering reversal of goal difference, would keep Wycombe in the second tier.
But keeping their heads above water for so long - largely thanks to four wins in seven games - is an achievement to be proud off for Ainsworth.
"This club is at 40 points. There's no R next to our name," said the manager, whose side have been bottom since December.
"It's going to take until the last whistle of the last day for us to be relegated, if that happens. I couldn't be prouder with that stat. It's phenomenal.
"We've upset the odds once again, but the boys deserved the win. The goal was fantastic, the defensive display was brilliant and the work-rate from some of the boys was just brilliant.
"This excites me for next year, never mind next week. Five years ago, we were looking at the trap door in non-league and what an achievement that is.
"Hopefully we can finish this season with a cherry on top next week with a win.
"I can't wait for the future of this football club. It's really exciting. Wycombe aim to be back in the Championship at the end of next season, that's what I want. That's what I'll be aiming for.
"We're going to end up one or two points away from survival which honestly is beyond our wildest dreams."
Ikpeazu's fourth-minute strike may well be a late contender for Wycombe's goal of the season.
First controlling on the edge of the area, the Ugandan turned and unleashed a curling effort that left Championship goalkeeper of the season Asmir Begovic stranded.
Bournemouth had already secured a top-six finish but they will earn a home play-off semi-final second leg should they beat Stoke and Swansea lose at promoted Watford on the final day.
Manager Jonathan Woodgate said: "We didn't want to risk players. But if players get injured then I need others like Jack Wilshere and Sam Surridge to get minutes in games like this.
"We've still got momentum. Out of nine (league) games, we've won seven. That's fantastic in any stretch of the imagination.
"Fair play to Wycombe, they scored an absolute worldie.
"We knew they were going to create chances, but we thought we had some gilt-edged chances, especially in the second half that we should have done better with.
"One of their centre-halves cleared it off the line with his hand and it's an open goal for David Brooks.
"But with just the one injury coming out of the game and the other players aren't injured, it's a positive at this stage of the season.
"I couldn't fault the players. I think they've done well on a difficult pitch. We move on to the next game with Stoke."